1. Field of the Invention
The present invention refers to an integrated all-Si capacitive microgyroscope with vertical differential Sense and Control and process for preparing an integrated all-Si capacitive microgyro with vertical differential Sense.
2. Description of Related Art
U.S. Pat. No. 5,894,090 to Tang et al., which is incorporated herein by reference, discloses a micromachined symmetrical leaf structure having a plurality of symmetrically disposed leaves about a defined center. At least one micromachined spring is disposed symmetrically with respect to the symmetrical leaf structure and supporting the symmetrical leaf structure, a rim/base structure to which the spring is coupled. The rim/base structure includes a plurality of sensing and drive electrodes and a circuit electrically coupled to the electrodes included within the rim/base structure. The circuit provides drive signals to the drive electrodes to oscillate the symmetrical leaf structure and to receive a sensing signal from the sensing electrodes to detect response of the oscillating symmetrical leaf structure to physical phenomena exterior to the micromachined resonator. The micromachined resonator has a manually inserted post. It shows a lack of a silicon based vacuum encapsulation. A low yield is obtained during the separation. The manufacturing of the resonator involves high fabrication costs. It shows large vibration sensitivity and no clear path to electronic integration.
The known manufacturing processes make it very difficult to manufacture a microgyroscope. The central post is inserted by hand, the device has to be vacuum packaged in a custom package and there is no ability to integrate control electronics with the silicon structure.
What is needed is a cloverleaf microgyroscope and a process for manufacturing a cloverleaf microgyroscope with an integrated central post and electronics with the resonator and vacuum package at wafer-level with a single crystal silicon construction.